Police are still attempting to tally all the stolen memorabilia taken in a recent burglary of the Yogi Berra Museum and Learning Center in Montclair, New Jersey.

The New York Daily Newsreports that police believe a team of “professional” robbers broke into the building Tuesday night and made off with a number of “priceless” baseball keepsakes housed within the facilities.

Authorities report that the thieves made their way into the museum through Yogi Berra Stadium, which connects to the exhibit and is used by the minor league New Jersey Jackals baseball team.

It’s unclear what is missing from the museum, as authorities are still attempting to get a hard list of the stolen articles. In the New York Daily News article, a source claims the thieves targeted “specific” and “valuable” pieces.

Berra’s museum boasted all 10 of the New York Yankees catcher’s World Series rings. Other “priceless” mementos on display in the stadium are Berra’s two MVP awards andseveral broken bats swung by the likes of Willie Mays, Stan Musial and other pros.

Sports memorabilia expert Rob Lifson told the New York Daily News the items stolen are likely singular in nature and would be almost impossible to sell without arousing suspicion.

“This is very unique material and it would have to stay underground,” Lifson said. “These are not mass-produced items...it’s like trying to sell a famous painting. Anyone who bought them would have to keep it secret. Why not just steal the Mona Lisa and try to sell that instead?”

The news of the break-in surely comes as another blow to Berra, who suffered the passing of his longtime spouse, Carmen, in March.

On the bright side, police officials have experienced some success in the last year in tracking down and finding baseball memorabilia thieves.

Twenty-four-year-old Isiah Slaton and two alleged accomplices made off with two of Aaron’s cars and a number of his baseball rings before being caught by authorities. Slaton was sentenced to eight years in prison and 42 years of probation for his crimes.